Ok this isn’t all that impressive by size but it’s taken me much longer to get here than I’d like to admit. It’s my first two sided milling that I actually got to work.
A friend of mine came to me with a piece from a collapsible ladder he has that broke. The manufacturer doesn’t sell the piece by itself so he asked if I could 3d print it.
Due to the size and design I didn’t think a 3d print would be very strong. So I thought about milling it out on my mpcnc.
I modeled it in fusion and spent far too long trying to set up the tool paths so I took it into estlcad and set it up pretty quickly. After a BUNCH Of iterations trying to mill it out of some plastic graphite stuff I had lying around, I finally had an epiphany. I poured a block of epoxy and just killed it out of that. I messed up the first try as the cleanup pass chipped a hunk off. In the end I finally got a finished piece that looks pretty decent.
I think the thing I’m most impressed with is that I mistakenly thought making my mpcnc large-ish (3’x3’ usable area) was a good idea. Well, it’s a little wobbly at times but I was quite surprised it could still mill something this small with a pretty decent accuracy.
Thanks. It’s amazing the number of face slap issues I had with milling that little part. Something so small should not have been so frustrating!
I do have to say, for anyone wanting to do two-sided milling, estlcam makes it INSANELY easy! It still has some gotchas but way easier than what I was trying to do in Fusion.
No I’m just using estlcam for the gcode generation. I’ve got a raspberry pi hooked up to my cnc running cnc.js and it works really well for that part.
Regarding what made it easy, you just bring in the 3D object you want to mill. Then you specify the material width/height/length and then a roughing pass tool and process and then a finishing pass tool and process. I don’t know if it’ll work as easily for all two-sided millings but it sure worked for me this time.
The hardest part was I had to make some programs for milling the bolt holes for holding it exactly right each time even after it flips. I just used inkscape to make a square the size of the material I specified in estlcam with bolt holes outside where I was eventually going to be milling. After that, I used estlcam to program the bolt hole clearing process. That way all the sizes for things were the same and everything was centered correctly.
I also set up some gcode macros in cnc.js to zero everything with the z probe I have. Then another macro that moved to the top, bottom, left corner of the material and zeroed out the axes. This way I had a very consistent 0,0,0 each time.
Setting all that up took a while but it’s made it possible to get pretty good results. I’ll try to put together a video some time of the whole process even though I’m sure lots of people have already
I had a heck of a time with estlcam trying two-sided milling, mainly because I couldn’t figure out an easy way to get the zero in the right place. Estlcam ignores the coordinates of the stl and always places zero at the lower left corner.
I wont bore you with the details, suffice to say it is an accomplishment.
